Wastewater treatment and other water treatment schemes are useful for providing treated water for numerous uses, particularly in locations where access to sufficient fresh water (sometimes referred to as “white water”) is limited. There are several treatment methods in use, ranging from primary settling treatment through secondary and tertiary treatment regimes, each using various degrees of physical sedimentation and floatation, biological treatment, filtration, chlorination, ozonation, and so on.
There are several types of filtration systems in use, depending on the type and quality of both the water being treated and the desired end use of that water. With particular regard to commercial scale filtration systems, examples include hollow fiber filters with pore sizes in the micrometer and nanometer range. Smaller pore sizes are found in reverse osmosis systems which may be used for example to de-salinate sea water for human consumption.
Given the way in which filters work, that is to provide a barrier to undesired material in the water, they eventually build up residue on their upstream surface. This residue can reduce the performance of the filter and therefore must regularly be cleaned. Cleaning regimes may include liquid or gas backwashing, gas scouring, or chemical treatment.